Rangers from Queensland Parks and Wildlife Service were assisted by members of the public with the attempted rescue of the dugong calf after it was found washed up on Pallarenda beach.

It was taken to the Reef HQ aquarium for temporary care.

A DES spokesman said despite a number of attempts to refloat the dugong calf, the animal continued to beach itself and its mother was not seen in area.

"As the animal could not survive in the wild without its mother … the department has liaised with vets to decide the best outcome for the animal in relation to its welfare," he said.

"Unfortunately in this situation, experts determined the dugong should be euthanised to prevent further suffering.

"A release into the wild without its mother would likely have only prolonged its suffering." The DES spokesman said appropriate housing facilities to care for dugongs in captivity didn't exist in Townsville and were not available in other parts of Queensland.

"DES staff wish to thank the members of the public who assisted in the attempted rescue by reporting the dugong to the appropriate authorities," he said.